1. Field of the Invention
The present invention relates generally to mail processing systems and equipment and, more specifically, to a transport/stacker module for a flats mail sorter system.
2. Description of the Related Art
A typical automated mail system includes a mail induction system and a transport system. As shown in FIGS. 1 and 2, the mail induction system 10 feeds pieces of mail to an oval or "race track" transport conveyor 12 which carries a plurality of mail piece carriers 14. The induction system 10 delivers one mail piece to each carrier 14 as the carriers travel in a given direction (counterclockwise in FIG. 1).
A plurality of bins 16 are disposed under the movable carriers 14. Each bin 16 is designated for a particular mail stop, address, etc., and a pivotally mounted rake 18 is disposed over the carriers 14 at each bin 16. When a piece of mail arrives over its destination bin, the rake 18 is actuated to pivot downwardly to push the mail piece off the carrier and into the designated bin.
As shown in FIGS. 3 and 4, the rake 18 is mounted on a shaft 20 journalled in a pair of supports 20a and 20b carried by the frame (not shown) and includes a plurality of rake tines 22 which interleave with slots 24 formed in a forward, angled end 26 of the carrier 14. A bottom 28 of the carrier 14 is integrally formed with the forward end 26.
Prior to actuation of the rake 18, the tines 22 are disposed horizontally (90.degree. counterclockwise rotated from the position illustrated in FIG. 3). A lever 30 is fixedly mounted on the shaft 20 in line with the tines 22. A push rod 32 has a proximal end pivotally connected to the lever 30 and a distal end which is unattached. A spring 34 has a coiled portion, through which the push rod 32 extends, a first end connected to the lever 30 and a second, opposite end connected to a second lever 36. The lever 36 is fixedly mounted on and rotatable with a second shaft 38. When the tines 22 and lever 30 are in a substantially horizontal position, the push rod 32 abuts against the upper end of the lever 36 and causes same to rotate counterclockwise with the shaft 38 until it reaches a nearly horizontal disposition.
As seen in FIG. 3, the shaft 38 carries an arm 40 which functions as a retarder such that, as the carrier 14 moves under the rake 18 when the rake is actuated to the vertical position by an actuator (not shown), the arm 40 rotates clockwise to engage a mail piece 42 as the rake 18 pushes the mail piece 42 off the carrier 14. The mail piece 42 may be a piece of "flats mail" which generally refers to magazines, large envelopes, newspapers, circulars, catalogs, digests, etc. The arm 40 is intended to control the "bounce back" of the mail piece caused by the rake tines 22 to allow neat stacking of the mail in the bins 16. An adjustable stop 44 provides a limit to the downward movement of the arm 40.
The system described above, and others of similar construction, have certain inherent deficiencies. First of all, the carriers have one open end and another end with a fixed end plate. The open end is a source of potential loss of mail pieces during transport, while the fixed end limits discharge of the mail piece to one direction. Moreover, the rake mechanism and retarder arms require a rather complex linkage to interconnect the two.
Also, the oval, horizontally oriented conveyor 12 requires a large amount of floor space and is not easily expanded to accommodate additional bins.